What is the best potting soil to use for Venus Fly Traps?

Be careful with that question. It is a bit misleading. Venus Fly traps actually can’t be planted in standard potting soil. They need nutrient poor, acidic media to survive. The most widely used media for Venus Fly Traps is a 1:1 combination of peat moss and perlite. For more information read the topic on soil for venus fly traps.